Method for operating a gate driver, gate driver, and drive assembly

Abstract

The present invention relates to a method for operating a driver for an electrical component. [Solution] An electrical first component is controlled by a first PWM signal (4) having a first frequency (5); a second PWM signal (6) having a second frequency (7) higher than the first frequency (5) is generated in the driver (1); the electrical second component is controlled using the second PWM signal (6), thereby charging an output capacitor (9); and at the rising edge of the first pulse of the first PWM signal (4), a first current signal (13) having a first voltage (14) from the output capacitor (9) is applied to the first component.

Description

Technical Field

[0001] The present invention relates to a method for operating a driver (gate driver), a driver (gate driver), a drive assembly, a power train, and a motor vehicle.

Background Art

[0002] A gate driver (so-called gate driver, isolated converter, or flyback controller) is typically an isolated power source used in converters (e.g., also in rectifiers, i.e., inverters, or DC-DC converters), which are, for example, intended for use in traction drives.

[0003] The converter converts, for example, a direct current taken from a traction battery into an alternating current or a direct current of a higher voltage and uses it to drive a traction drive. Inside the converter, the energy or power required to drive the traction drive is converted and supplied via power electronics.

[0004] The adjustment of energy or power is usually carried out via a microcontroller, where the microcontroller provides a (first) PWM signal (pulse width modulation signal) on the low voltage side (primary side). This PWM signal on the low voltage side is converted by the gate driver into a gate signal on the high voltage side (secondary side), where the gate of the power switch is controlled by the gate signal. As a result of the gate signal, the power switch is controlled such that the current required to drive the traction drive is supplied via the power switch.

[0005] The gate driver directs an electrically isolated (first) PWM signal from the converter's microcontroller to the gate of a (e.g., IGBT / SiC / GaN) power switch (IGBT: insulated-gate bipolar transistor, SiC: silicon carbide, GaN: gallium nitride). Thus, the gate driver protects people and equipment from voltage-induced hazards. For this purpose, the gate driver generates positive and negative output voltages for the power switch on the high-voltage side, and as a result, in response to the first PWM signal from the microcontroller on the low-voltage side, the gate is opened (the gate driver provides a positive (first) voltage to the gate) or closed (the gate driver provides a negative (second) voltage to the gate).

[0006] These positive (first) and negative (second) voltages are generated by a separate control unit of the gate driver. The energy required to switch the gate is stored in the so-called (buffer) output capacitors of this control unit. To charge these output capacitors, the control unit is activated on the low-voltage side with its own second PWM signal, which is then transferred to the galvanically isolated high-voltage side and used to charge the output capacitors located there. This second PWM signal has a much higher (constant) frequency than the first PWM signal. The second PWM signal may have a constant pulse duration and a corresponding constant pause duration, or it may have load-dependent variable pulse duration and pause duration, respectively.

[0007] The low-voltage and high-voltage sides of the gate driver are galvanically isolated from each other. The gate driver allows high current to be supplied to switch the power switch, meaning that SiC and IGBT power switches designed for hundreds of kilowatts of drive power can also be switched without the need for additional external buffers.

[0008] Gate drivers are generally supplied as separate electronic modules. Modern and future semiconductor generations of IGBT / SiC gate drivers include the gate driver circuitry within the IC chip (internal controller of the IC), eliminating the need for a separate chip and associated housing.

[0009] The secondary (high-voltage) side control of a gate driver is used to generate a precise output voltage (either the first or second voltage). When the power switch is turned on, a large current (tens of amperes) is drawn from the gate driver or its high-voltage side. For this reason, a large capacitance value in the range of tens of microfarads is required on the high-voltage side to provide stabilization and minimize voltage drop. These capacitances are also referred to as (buffer) output capacitors. [Overview of the project] [Problems that the invention aims to solve]

[0010] A problem with existing gate drivers is that a voltage drop occurs at the output capacitor when the power module or power switch is switched on due to the gate current. Therefore, conventional gate drivers require a large output capacitor. If the capacitor is designed to be too small, the voltage required to switch the gate may not be provided. Consequently, the required traction drive power cannot be delivered. The considerable size and weight of these capacitors required for this purpose can increase their cost. In addition, the performance of a gate driver can be affected by a large output capacitance. This can affect the transient response and result in slower voltage regulation.

[0011] A similar problem exists in the power output of a DC-DC converter. Here, the battery voltage is adjusted by the DC-DC converter to the voltage required to operate an electric motor. In addition, power is made available to the motor as needed. To start the motor, a bridge is usually provided, which is started via a first PWM signal from the control unit. An output capacitor (or multiple capacitors) is usually provided between the converter and the bridge, from which additional energy may be supplied. If the capacitor is designed to be too small, the power required to operate the motor may not be immediately available at times.

[0012] The object of the present invention is to solve, at least partially, the problems raised in relation to the prior art. In particular, a method for operating a gate driver should be proposed, which will enable reliable gate switching on the one hand and reduce the cost of the gate driver on the other hand. In particular, a method for operating the driver should be additionally proposed, which can reduce or prevent potential delays in supplying power to an electric motor. [Means for solving the problem]

[0013] A method having the features described in claim 1 contributes to solving these problems. Advantageous extensions are the subject of the dependent claims. The features individually listed in the claims can be combined with each other in any technically meaningful way and can be supplemented by descriptive descriptions from the description and / or details from the drawings, where further design modifications of the present invention are demonstrated.

[0014] A method is proposed for operating a driver for an electrical component, where a first electrical component is controlled by a first PWM signal having a first frequency (constant or variable). The driver generates a second PWM signal having a second frequency (constant or variable) that is (always) higher than the first frequency. The second PWM signal is used to control a second electrical component, thereby charging an output capacitor. At the rising edge of the first pulse of the first PWM signal, a first current signal having a first voltage from the output capacitor is applied to the first component. This method is, a) A step of generating a second PWM signal (6) using a second pulse (19) having a first pulse duration (20), b) A step of detecting when the rising edge (11) of the first PWM signal (4) begins, c) A step of changing the second PWM signal (6) by extending the first pulse duration (20) to the second pulse duration (21), It has.

[0015] The driver is particularly suited for activating an electrical component (e.g., a DC-DC converter and a bridge) and comprises a control unit. The driver can receive or generate a first PWM signal having a first frequency and generate a second PWM signal having a second frequency higher than the first frequency. As described above, the first PWM signal is used to activate the bridge (as a first electrical component). The second PWM signal is used to activate the converter (as a second electrical component). The converter may be used to charge a capacitor located between the converter and the bridge. This method may be used to perform this charging in a targeted manner in response to the first PWM signal. The second PWM signal is varied in response to the first PWM signal.

[0016] A driver is, in particular, part of a drive assembly comprising at least one electric motor and a converter and bridge. A DC-DC converter is used to convert energy from a battery and transfer it to an electric motor. The drive assembly includes a control unit, which regulates the current transferred from the converter to the motor. The drive assembly includes a driver, which is suitable for starting the drive assembly or the converter and bridge.

[0017] In particular, or alternatively, the driver is a gate driver (isolated converter or flyback controller), which is suitable for activating the gate (as the first electrical component) of a power switch. The gate driver controls the gate of the power switch. The gate is controlled by a first PWM signal having a first frequency. A second PWM signal is generated in the gate driver at a second frequency, where the second PWM signal is applied to the gate driver circuit (as the second electrical component), which comprises at least one first output capacitor and a second output capacitor to charge the output capacitors.

[0018] A method for operating a gate driver is (additionally) proposed. The gate driver controls the gate of a power switch (e.g., IGBT / SiC / GaN). The gate is controlled by a first PWM signal having a first frequency (constant or variable). The gate driver generates a second PWM signal having a second frequency (constant or variable) that is (always) higher than the first frequency. The second PWM signal is applied to a gate driver circuit having at least one first output capacitor and a second output capacitor in order to charge the output capacitors.

[0019] At the rising edge of the first pulse of the first PWM signal, a first current signal having a first voltage from the first output capacitor is applied to the gate, and at the falling edge of the first pulse, a second current signal having a second voltage from the second output capacitor is applied to the gate.

[0020] Starting from a first state where there is a pause between two first pulses, the method a) generates a second PWM signal having (successive) second pulses with a (constant) first pulse duration, b) detects that the rising edge of the first PWM signal starts, (and immediately thereafter) c) varies the second PWM signal by extending the first pulse duration to a (constant) second pulse duration and at least includes.

[0021] Alternatively or in addition to this, starting from a second state where the first pulse (already) exists, the method x) generates a second PWM signal using (successive) second pulses having a first pulse duration, y) detects that the falling edge of the first PWM signal starts, and z) varies the second PWM signal by extending the first pulse duration to a second pulse duration and at least includes.

[0022] In particular, a solution for an existing gate driver is proposed. In this regard, the operating mode of the above-mentioned gate driver is referred to. In particular, a method is proposed in which the voltage at the gate (or the absolute value of the related first or second voltage) should be increased based on the moment when the power switch is switched on. In this case, as part of a method for operating the gate driver of a power switch (in particular, an insulated gate bipolar transistor - IGBT), a second PWM signal that can be varied according to the first PWM signal is generated and provided. In particular, the duty cycle of the pulse width modulation (PWM) of the second PWM signal is increased.

[0023] In particular, this method can ensure that higher stabilization and lower voltage drop occur in the output capacitor when a large current flows when the power switch is switched on (or when the bridge is operated). The mechanism by which this is achieved includes, in particular, increasing the duty cycle of the second PWM signal as an (immediate) reaction to the rising edge of the first PWM signal, whereby a larger charge is generated in the output capacitor. This boost event (i.e., the increase in the duty cycle) can be used to reduce or even prevent the voltage drop in the output capacitor. In addition, even the capacitance of the associated output capacitor can be reduced, and as a result, the component cost of the (gate) driver and the space occupied by the (gate) driver can be reduced. The proposed method can improve the efficiency and reliability of power supply in systems using these power switches, for example.

[0024] In particular, the gate driver comprises a low-voltage side (primary side) and a high-voltage side (secondary side). In particular, the (first) PWM signal is provided by a microcontroller on the primary side of the gate driver. This first PWM signal is received in the first circuit of the gate driver.

[0025] The first PWM signal is used, in particular, to provide the energy required from the battery for the (traction) motor. This first PWM signal on the low-voltage side is converted by the gate driver into a gate signal on the high-voltage side (secondary side), where the gate of the power switch is controlled by the gate signal. The power switch is located on the secondary side. As a result of the gate signal, the power switch is controlled so that the current required to drive the traction drive is supplied through the power switch.

[0026] The gate driver generates positive and negative output voltages for the power switch on its high-voltage side (secondary side), and as a result, the gate is closed (the gate driver provides a positive (first) voltage to the gate) or opened (the gate driver provides a negative (second) voltage to the gate) in response to a first PWM signal from the microcontroller on the low-voltage side.

[0027] In particular, the gate driver includes a second circuit that generates a second PWM signal on the primary side. On the secondary side, the second PWM signal is used by the second circuit to charge an output capacitor. The output capacitor is part of the circuit that forms the secondary side of the second circuit.

[0028] The first output capacitor is particularly useful in providing a positive (first) voltage, which can be used to apply a first current signal to the gate of the power switch in order to switch, i.e., close, the power switch.

[0029] The second output capacitor is particularly useful for providing a negative (second) voltage, which can be used to apply a second current signal to the gate of the power switch in order to switch, i.e., open, the power switch.

[0030] Therefore, using the second circuit, a second PWM signal is generated on the primary side and used on the secondary side to charge the output capacitors. In addition, the gate is switched by the second circuit by discharging each output capacitor and by the current signal formed thereby.

[0031] During the discharge of the output capacitor, particularly at high currents, a voltage drop may occur across the output capacitor. This upward and downward voltage fluctuation across the output capacitor is also referred to as voltage fluctuation or voltage ripple. This voltage drop can be at least partially compensated, balanced, or overcompensated using this method.

[0032] This method distinguishes between two states in particular: 1) In the first state, there is a pause between the two first pulses. The pause ends on the rising edge. 2) In the second state, the first pulse already exists. The first pulse ends on a falling edge.

[0033] The duration of each first pulse or the pause between the first two pulses may vary (particularly depending on power requirements).

[0034] Starting from the first state, this method (for a driver or gate driver) a) To generate a second PWM signal (in accordance with the first PWM signal) having a second pulse (multiple consecutive pulses) having a first pulse duration (and a constant second frequency), (and thereafter) b) Detect the beginning of the rising edge of the first PWM signal, (and immediately thereafter) c) Varying the second PWM signal by extending the duration of the first pulse toward a (constant) second pulse duration (while maintaining a constant second frequency). This includes in particular.

[0035] Starting from the second state, this method (for gate drivers) x) Generate a second PWM signal (in accordance with the first PWM signal) having a second pulse (multiple consecutive pulses) having a first pulse duration (and a constant second frequency), (and thereafter) y) Detect the beginning of the falling edge of the first PWM signal, (and immediately thereafter) z) Varying the second PWM signal by extending the duration of the first pulse toward a (constant) second pulse duration (while maintaining a constant second frequency). This includes in particular.

[0036] By extending the pulse duration, the discharge of the output capacitor (which occurs particularly simultaneously with steps b), c), or y), z) respectively) can be at least partially compensated, fully compensated, or overcompensated.

[0037] In particular, the driver operates using at least one (or more, or all) of the following parameters (especially when used in conjunction with a DC-DC converter): *The first frequency (of the first PWM signal): at least 1 kHz; 1 MHz or less, especially 15 kHz or less; *The second frequency (of the second PWM signal): at least 10 kHz, especially at least 100 kHz; 100 MHz or less, especially 50 MHz or less, preferably 10 MHz or less; *The second frequency > 10 × the first frequency (i.e., the second frequency is always greater than the first frequency, and in particular at least 20 times greater); *Output capacitors (total): at least 1μF, especially at least 100μF; 10mF or less, especially 1mF or less; *Input voltage of the converter used as the first electrical component: at least 5V, especially at least 10V; 500 volts or less, especially 50 volts or less, preferably 20 volts or less; *Output voltage of the converter (first component): at least 10V, preferably at least 40 volts; 1,000V or less, especially 100V or less; *Input voltage of the second PWM signal (i.e., primary): at least 5V, especially at least 10V; 500V or less, especially 100V or less; *Pulse duration: at least 1%; less than or equal to 100%; where the second pulse duration > 1.5 × the first pulse duration, especially at least twice as large.

[0038] In particular, the gate driver operates (specifically to the gate driver) using at least one (or more, or all) of the following parameters: * (First frequency of the first PWM signal): at least 1 kHz; 20 kHz or less; *The second frequency (of the second PWM signal): at least 10 kHz, especially at least 100 kHz; 100 MHz or less, especially 50 MHz or less, preferably 10 MHz or less; *The second frequency > 10 × the first frequency (i.e., the second frequency is always greater than the first frequency, and in particular at least 20 times greater); *(First and second) output capacitors (in each case): at least 1 μF, especially at least 100 μF; 10 mF or less, especially 1 mF or less; *The first (nominal) voltage (when the first pulse duration is applied): at least 10V, especially at least 15V; 20V or less; *The second (nominal) voltage (when the first pulse duration is applied): at least -20V, 0V or less; -5V or less; *Input voltage of the second PWM signal (i.e., primary): at least 5V, especially at least 10V; 500V or less, especially 100V or less; *Pulse duration: at least 1%; less than or equal to 100%; where the second pulse duration > 1.5 × the first pulse duration, especially at least twice as large.

[0039] In particular (in the method for operating the driver and gate driver), the second pulse duration is maintained over at least two (optionally three, four, or more) second pulses, after which (i.e., after step c) or z)) the second PWM signal is changed or shortened (again) by shortening the second pulse duration.

[0040] In particular (in the method for operating the driver and gate driver), the second pulse duration is shortened (again) to the first pulse duration.

[0041] In particular (in a method for operating a driver and a gate driver), the pulse duration is equal to a constant absolute value of the first pulse duration (in step a) or x), or equal to a constant absolute value of the second pulse duration (in step c) or z).

[0042] In particular (in methods for activating drivers and gate drivers), the duration of the second pulse is maintained for at least (or up to) 20% of the duration of the first pulse, or (in methods for activating gate drivers) for at least (or up to) 20% of the duration of the pause between the two first pulses (particularly for at least or up to 40% of the duration, preferably at least or up to 60% of the duration, and particularly preferably at least or up to 80% of the duration).

[0043] In particular, steps a) to c) (in the method for activating the driver and gate driver) or steps x) to z) (in the method for activating the gate driver) are performed for each first pulse.

[0044] In particular, after each first pulse, or after each execution of step a) to c) of the method (in the method for activating the driver and gate driver) or step x) to z) (in the method for activating the gate driver), a second PWM signal having a first pulse duration is again present before a second PWM signal having a second pulse duration is generated again.

[0045] In particular, steps a) to c) (in the method for activating the driver and gate driver) and / or steps x) to z) (in the method for activating the gate driver) are repeated with each first pulse, and steps c) and z) are performed only in a time-limited manner.

[0046] In particular, by extending the pulse duration of the second PWM signal (in the method for operating the driver and gate driver), each (first / second) (nominal) voltage can be changed or increased in magnitude by at least (or up to) 10%, preferably at least (or up to) 15%, of the absolute value of that voltage.

[0047] Furthermore, a driver is proposed, which is suitable for activating an electrical component and comprises a control unit. The driver receives or generates a first PWM signal having a first frequency and generates a second PWM signal having a second frequency higher than the first frequency. The control unit is suitable for performing the described method, and the second PWM signal may be varied in accordance with the first PWM signal.

[0048] The driver is particularly suitable for activating electrical component components (e.g., DC-DC converters and bridges). As described above, the first PWM signal is used to activate the bridge (as the first electrical component). The second PWM signal is used to activate the converter (as the second electrical component). The converter may be used to charge a capacitor located between the converter and the bridge. This method may be used to perform this charging in a targeted manner in response to the first PWM signal. The second PWM signal is varied in response to the first PWM signal.

[0049] A driver is, in particular, part of a drive assembly comprising at least one electric motor and converter, as well as a bridge (as an electrical component). The DC-DC converter is used to convert energy from the battery and transfer it to the electric motor. The drive assembly comprises a control unit, which regulates the current transferred from the converter to the motor. The drive assembly comprises a driver, which is suitable for starting the electrical component components of the drive assembly (e.g., the converter and the bridge).

[0050] In particular, or alternatively, the driver is a gate driver (isolated converter or flyback controller), which is suitable for activating the gate (as the first electrical component) of a power switch. The gate driver controls the gate of the power switch. The gate is controlled by a first PWM signal having a first frequency. A second PWM signal is generated in the gate driver at a second frequency, where the second PWM signal is applied to the gate driver circuit (as the second electrical component), which comprises at least one first output capacitor and a second output capacitor to charge the output capacitors.

[0051] Accordingly, a gate driver is proposed, which is further appropriately designed to activate the gate (as an electrical first component) of a power switch. The gate driver has a primary side, a secondary side galvanically isolated from the primary side, and a control unit. The gate driver comprises at least one first circuit for receiving a first PWM signal having a first frequency on the primary side, and a second circuit on the primary side for generating a second PWM signal having a second frequency higher than the first frequency. The second circuit on the secondary side comprises at least one first output capacitor and a second output capacitor. The output capacitors can be charged via the second PWM signal, and a gate located on the secondary side can be switched by at least partially discharging the respective output capacitors. The control unit is suitable for carrying out the described method (particularly with respect to the gate driver) or comprises means for carrying out steps of the method, and / or is appropriately equipped, configured or programmed or comprises means for carrying out the method. The second PWM signal can be varied in response to the first PWM signal (particularly with respect to the duration of the first or second pulse, especially by the control unit).

[0052] Further proposed is a drive assembly comprising at least an electric motor, a converter for converting energy from a battery and transferring it to the electric motor, and a control device, wherein the control device adjusts the current transmitted from the converter to the motor, and the drive assembly comprises a described driver suitable for invoking the components of the drive assembly (i.e., the converter and the bridge), or means for invoking the drive assembly, and / or means appropriately equipped, configured or programmed for operating the drive assembly.

[0053] In particular, the converter is a DC-DC converter. Specifically, the input voltage of the converter in this case is at least 5 volts and 500 volts or less, particularly at least 10 volts and 50 volts or less or 20 volts or less. Specifically, the output voltage of the converter is at least 10 volts and 1000 volts or less, preferably at least 40 volts and 100 volts or less.

[0054] In particular, the converter is a DC-DC converter, and a so-called or known B6 / H bridge is placed between the motor and the converter. In particular, the converter is connected to the battery via a filter. In particular, the first frequency of the first PWM signal that operates the bridge is at least 10 kHz and 1 MHz or less, preferably at least 5 kHz and 100 kHz or less. In particular, the second frequency of the second PWM signal applied to the converter is at least 10 kHz and 100 MHz or less, particularly at least 1 MHz and 10 MHz or less.

[0055] In particular, the current regulated by the control device is transferable between the converter and the motor via at least one power switch, and the drive assembly includes a described gate driver suitable for activating the gate of at least one power switch.

[0056] In particular, the converter is a DC-AC converter (a so-called inverter).

[0057] A further drivetrain for automobiles has been proposed, which comprises at least a battery (also called a secondary battery) for storing electrical energy, and a described drive assembly, where a motor (also called a traction drive) may be connected to a drive shaft to transmit torque, and a converter suitable for transferring energy from the battery to the electric motor and from the electric motor to the battery.

[0058] At a minimum, an automobile is further proposed that has the described drivetrain and a drive shaft connected to the engine for transmitting torque. The automobile may also have multiple drive shafts (driven by one motor or by other motors).

[0059] In particular, the control unit and / or control device is provided as a data processing system, which is appropriately equipped, configured or programmed to perform a method or to activate a gate, or comprises means for performing a method and / or activating a gate.

[0060] The means includes, for example, a processor, a memory storing commands to be executed by the processor, and data or signal lines or transmission devices that enable the transmission of commands, measurements, data, etc., between specified elements.

[0061] "Means" may include, in particular, one or more of the following components: a controller, a microcontroller, data storage, data connectivity, a display device (such as a display), a counter or timing element (a timer), at least one additional sensor, an energy source, etc.

[0062] Furthermore, a computer program is proposed which includes commands that cause the computer to perform the described method or steps of the described method while the computer is executing the computer program.

[0063] Furthermore, a computer-readable storage medium is proposed, which includes commands that cause the computer to perform the described method or steps of the described method while the computer is running.

[0064] Embodiments of the method are particularly applicable to drive assemblies, drivetrains, automobiles, control devices, or data processing systems, and / or computer implementations (i.e., computer programs and computer-readable storage media), and vice versa.

[0065] Therefore, two different applications of the described method are proposed in particular. Firstly, with respect to the driver, which is used to control a drive assembly comprising, for example, a DC-DC converter (second component), a bridge (first component), and a motor. The capacitance provided between the converter and the bridge is (re)charged as quickly as possible so that the power required to operate the motor is always available.

[0066] Secondly, there is a gate driver, which is suitable for activating the gate of the power switch (as the first component). The gate driver controls the gate of the power switch. A second PWM signal is generated in the gate driver, where the second PWM signal is applied to the gate driver circuit (as the second electrical component), which comprises at least one first output capacitor and a second output capacitor to charge the output capacitors.

[0067] The use of indefinite articles ("a", "an") should be understood as such, particularly in claims and descriptions that reflect them, and not as numerals. Thus, terms or components introduced should be understood to mean that there is at least one of them, and in particular, there may be multiple.

[0068] For the sake of clarity, please note that the numbers used herein ("first," "second," etc.) are primarily intended to distinguish multiple objects, variables, or processes of the same type, and do not, in particular, specify any dependencies and / or order of these objects, variables, or processes relative to one another. Where dependencies and / or order are required, this will be explicitly stated herein or will become apparent to those skilled in the art when considering the specific embodiments described. Where multiple components may appear ("at least one"), the description given for one of these components may, though not required, apply equally to all or some of the multiple components.

[0069] The present invention and its technical background will be described in more detail below with reference to the accompanying drawings. It should be noted that the present invention is not intended to be limited by the exemplary embodiments cited. In particular, it should be noted that the figures, and especially the proportions shown in the figures, are approximate. [Brief explanation of the drawing]

[0070] [Figure 1] This shows a car equipped with a drivetrain. [Figure 2] This shows a gate driver and a power switch. [Figure 3] The first graph is shown. [Figure 4] The second graph is shown. [Figure 5] This shows the illustration of steps a), b), c), or x), y), z). [Figure 6]A third graph is shown, accompanied by a comparison of steps a) and c) or x) and z). [Figure 7] A fourth graph illustrating the effectiveness of the method is shown. [Figure 8] This shows the constituent elements. [Modes for carrying out the invention]

[0071] Figure 1 shows an automobile 35 comprising a drivetrain 34 and a drive shaft 36 connected to a motor 30 for transmitting torque. Furthermore, the drivetrain 34 includes a converter 31 for transferring energy from a battery 32 to an electric motor 30 and from the electric motor 30 to the battery 32. In addition, the drivetrain 34 or automobile 35 includes a control unit 33. The motor 30 and the converter 31 together with the control unit 33 form a drive assembly 29. The control unit 33 regulates the current 38 transferred from the converter 31 to the motor 30 via at least one power switch 3.

[0072] Figure 2 shows the gate driver 1 and the power switch 3. Refer to the explanation given for Figure 1.

[0073] The drive assembly 29 shown in Figure 1 includes a gate driver 1 suitable for activating the gate 2 of the power switch 3.

[0074] The gate driver 1 is suitable for activating the gate 2 of the power switch 3. The gate driver 1 comprises a primary side 24, a secondary side 25 galvanically isolated from the primary side 24, and a control unit 26, in a known manner. The gate driver 1 includes a first circuit 27 on the primary side 24 for receiving a first PWM signal 4 having a first frequency 5. Furthermore, the gate driver 1 includes a second circuit 28 on the primary side 24 for generating a second PWM signal 6 having a second frequency 7 higher than the first frequency 5. The second circuit 28 has a first output capacitor 9 and a second output capacitor 10 on the secondary side 25. The output capacitors 9 and 10 can be charged via the second PWM signal 6, and the gate 2 located on the secondary side 25 can be switched by at least partially discharging the respective output capacitors 9 and 10. The control unit 26 is suitable for performing the method described below.

[0075] In contrast to the known gate driver 1, the second PWM signal 6 can be varied in a specific way in response to the first PWM signal 4 (particularly with respect to the first or second pulse durations 20, 21, especially by the control unit 26).

[0076] Figure 3 shows the first graph. Figure 4 shows the second graph. Figure 5 shows an illustration of steps a), b), c) or x), y), z). Figure 6 shows the third graph with a comparison of steps a) and c) or x) and z). Figure 7 shows the fourth graph showing the effect of the method. Figures 3 through 7 are described together below. The descriptions given for Figures 1 and 2 are referenced.

[0077] In the first graph shown in Figure 3, the current 38 of one phase of the motor 30 is shown on the vertical axis at the top, and time 37 is shown on the horizontal axis. At the bottom of Figure 3, the vertical axis represents the first PWM signal 4 that generates the current 38, and the horizontal axis represents time 37.

[0078] In the second graph shown in Figure 4, the third graph shown in Figure 6, and the fourth graph shown in Figure 7, voltages 14 and 17 are plotted on the vertical axis, and time 37 is plotted on the horizontal axis.

[0079] The gate driver 1 is an isolated power supply typically used in a converter 31 (for example, a rectifier, i.e., an inverter, or a DC-DC converter), and these are intended for use, for example, in traction drives.

[0080] The converter 31 converts, for example, the DC current drawn from the traction battery 32 into AC current or a higher voltage DC current, which is then used to drive the traction drive or motor 30. Within the converter 31, the energy or power required to drive the traction drive 30 is converted and supplied via power electronics.

[0081] Energy or power regulation is typically performed via a microcontroller (specified here by control unit 26), which provides a first PWM signal 4 on the low-voltage side (primary side 24). This first PWM signal 4 on the primary side 24 is converted by a gate driver 1 into gate signals (current signals 13, 16) on the high-voltage side (secondary side 25), where the gates 2 of the power switch 3 are controlled by the current signals 13, 16. As a result of the current signals 13, 16, the power switch 3 is controlled so that the current 38 necessary to drive the motor 30 is supplied through the power switch 3.

[0082] The gate driver 1 directs a first PWM signal 4, electrically isolated from the control unit 26 of the converter 31, to the gate 2 of the power switch 3. The gate driver 1 generates positive and negative output voltages for the power switch 3 on the secondary side 25, and as a result, the gate 2 is closed (the gate driver 1 provides a positive first voltage 14 to the gate 2) or opened (the gate driver 1 provides a negative second voltage 17 to the gate 2) in response to the first PWM signal 4 from the control unit 26 on the primary side 24.

[0083] The positive first voltage 14 and the negative second voltage 17 are generated via a separate control unit (second circuit 28) of the gate driver 1. The energy required to switch the gate 2 is stored in the so-called (buffer) output capacitors 9 and 10 of this second circuit 28. To charge these output capacitors 9 and 10, the control unit 26 is activated on the low-voltage side (primary side 24) with its own second PWM signal 6, which is transferred to the galvanically isolated high-voltage side (secondary side 25) and used to charge the output capacitors 9 and 10 located there. This second PWM signal 6 has a significantly higher (constant) second frequency 7 than the first PWM signal 4, and also has a constant first pulse duration 20 and a corresponding constant duration 23 of pause 18 (see Figure 4). The second PWM signal 6 is provided on the primary side 24 using an input voltage 22.

[0084] The low-voltage (primary side 24) and high-voltage (secondary side 25) sides of the gate driver 1 are galvanically isolated from each other. The gate driver 1 allows a high current to be supplied to switch the power switch 3, which means that the SiC and IGBT power switches 3, designed for drive powers of several hundred kW, can also be switched without the need for additional external buffers.

[0085] The secondary (high-voltage side) control (second circuit 28) of the gate driver 1 is used to generate a precise output voltage (first voltage 14 or second voltage 17). When the power switch 3 is switched on, a large current 38 (tens of amperes) is drawn from the gate driver 1 or its secondary side 25. For this reason, a large capacitance value in the range of tens of microfarads is required on the secondary side 25 to provide stabilization and minimize voltage drop. These are also referred to as (buffer) output capacitors 9, 10. The voltage drop of such a voltage (first voltage 14) is shown in Figure 4.

[0086] A problem with existing gate drivers 1 is that when the power module or power switch 3 is switched on due to the gate current 38, a voltage drop occurs in the output capacitors 9 and 10. Therefore, conventional gate drivers 1 require large output capacitors 9 and 10. If capacitors 9 and 10 are designed to be too small, the voltages 14 and 17 required to switch the gate 2 may not be provided at times. Consequently, the power required for the traction drive or motor 30 may not be provided. The considerable size and weight of these capacitors 9 and 10 required for this purpose can increase their cost. In addition, the performance of the gate driver 1 can be adversely affected by the large output capacitance. This can affect the transient response and result in slower voltage regulation.

[0087] In the method described herein, the gate 2 of the power switch 3 is controlled via a gate driver 1. The gate 2 is controlled by a first PWM signal 4 having a constant first frequency 5 (see Figures 3 and 4, and the top of Figure 5). In the gate driver 1, a second PWM signal 6 is generated using a constant second frequency 7 that is always higher than the first frequency 5 (see Figures 4 and 5). The second PWM signal 6 is applied to a circuit 8 of the gate driver 1 having a first output capacitor 9 and a second output capacitor 10 in order to charge the output capacitors 9 and 10.

[0088] At the rising edge 11 of the first pulse 12 of the first PWM signal 4, a first current signal 13 having a first voltage 14 from the first output capacitor 9 is applied to the gate 2, and at the falling edge 15 of the first pulse 12, a second current signal 16 having a second voltage 17 from the second output capacitor 10 is applied to the gate (see Figures 2, 3, and 4).

[0089] The described method is intended as a proposed solution for an existing gate driver 1. A method is proposed in which the voltages 14, 17 (or the absolute value of the associated first or second voltage) at gate 2 should be increased based on the moment when power switch 3 is switched on. In this method, as part of the method for activating the gate driver 1 of power switch 3, a second PWM signal 6 is generated and provided which can be varied in response to a first PWM signal 4. This involves increasing the duty cycle of pulse width modulation (PWM) of the second PWM signal 6.

[0090] This method can be used to ensure that higher stabilization and lower voltage drop are present or occur in the output capacitors 9 and 10 when a large current 38 flows when the power switch 3 is switched on. The mechanism by which this is achieved consists of increasing the duty cycle of the second PWM signal 6 as an (immediate) response to the rising edge 11 of the first PWM signal 4 (see Figures 5 and 6), thereby generating a larger charge in the output capacitors (one or more) 9 and 10. This boost event (i.e., increase in duty cycle) can be used to reduce or even prevent the voltage drop in the output capacitors 9 and 10 (see Figure 7). In addition, even the capacitance of the associated output capacitors 9 and 10 can be reduced, resulting in a reduction in the component cost of the gate driver 1 and the space occupied by the gate driver 1. The proposed method can improve the efficiency and reliability of power supply in systems using these power switches 3.

[0091] Starting from a first state in which a pause 18 occurs between two first pulses 12, the method includes at least steps a) to c). According to step a), a second PWM signal 6 is generated using (a number of consecutive) second pulses 19, where the second pulses 19 have a constant first pulse duration 20 (see top of Figures 5 and 6). According to step b), the rising edge 11 of the first PWM signal 4 is detected to have begun (see Figure 5). Immediately thereafter, according to step c), the second PWM signal 6 is modified by extending the first pulse duration 20 to a constant second pulse duration 21 (see Figures 5 and 6).

[0092] Alternatively, or in addition to the above, starting from a second state in which the first pulse 12 already exists, the method includes steps x) to z). According to step x), a second PWM signal 6 is generated using a plurality of consecutive second pulses 19, each having the first pulse duration 20. According to step y), the beginning of the falling edge 15 of the first PWM signal 4 is detected. According to step z), immediately after step y), the second PWM signal 6 is modified by extending the first pulse duration 20 to the second pulse duration 21.

[0093] The gate driver 1 comprises a low-voltage side (primary side 24) and a high-voltage side (secondary side 25). The first PWM signal 4 is provided by the microcontroller on the primary side 24 of the gate driver 1. This first PWM signal 4 is received in the first circuit 27 of the gate driver 1.

[0094] The first PWM signal 4 is used to provide the necessary energy from the battery 32 for the (traction) motor 30. This low-voltage first PWM signal 4 is converted by the gate driver 1 to high-voltage (secondary side 25) gate signals 13, 16, where the gate 2 of the power switch 3 is controlled by the gate signals 13, 16. The power switch 3 is located on the secondary side 25. As a result of the gate signals 13, 16, the power switch 3 is controlled so that the current 38 necessary to drive the traction drive / motor 30 is supplied through the power switch 3.

[0095] The gate driver 1 generates positive and negative output voltages 14 and 17 for the power switch 3 on its high-voltage side (secondary side 25), and as a result, in response to the first PWM signal 4 of the microcontroller on the low-voltage side, the gate 2 is closed (the gate driver 1 provides a positive first voltage 14 to the gate 2) or opened (the gate driver 1 provides a negative second voltage 17 to the gate 2).

[0096] The gate driver 1 includes a second circuit 28, which generates a second PWM signal 6 on the primary side 24. On the secondary side 25, the second PWM signal 6 is used by the second circuit 28 to charge output capacitors 9 and 10. The output capacitors 9 and 10 are part of the circuit 8 that forms the secondary side 25 of the second circuit 28.

[0097] The first output capacitor 9 helps to provide a positive first voltage 14, which can be used to apply a first current signal 13 to the gate 2 of the power switch 3 in order to switch, i.e., close, the power switch 3.

[0098] The second output capacitor 10 helps to provide a negative second voltage 17, which can be used to apply a second current signal 16 to the gate 2 of the power switch 3 in order to switch, i.e., open, the power switch 3.

[0099] Therefore, using the second circuit 28, a second PWM signal 6 is generated on the primary side 24 and used on the secondary side 25 to charge the output capacitors 9 and 10. In addition, the gate 2 is switched by the second circuit 28 by discharging the respective output capacitors 9 and 10 and by the current signals 13 and 16 formed thereafter.

[0100] During the discharge of output capacitors 9 and 10, particularly at high currents 38, a voltage drop may occur in output capacitors 9 and 10 (see the first trace 39 in Figure 7). The upward and downward nature of the voltages 14 and 17 in output capacitors 9 and 10 is also referred to as voltage fluctuation or voltage ripple. Using this method, this voltage drop can now be at least partially compensated (see the second trace 40 in Figure 7), balanced (see the third trace 41 in Figure 7), or overcompensated (see the fourth trace 42 in Figure 7). The second trace 40 reaches the minimum value of the first nominal voltage 41 again only after a certain time 37. The third trace 41 runs between the minimum and maximum values ​​of the first nominal voltage 14. The fourth trace 42 temporarily exceeds the maximum value of the first nominal voltage 14.

[0101] This method distinguishes between two states. In the first state, there is a pause 18 between two first pulses 12. The pause 18 ends at the rising edge 11. In the second state, the first pulse 12 already exists. The first pulse 12 ends at the falling edge 15. The duration 23 of each first pulse 12 or the pause 18 between two first pulses 12 may vary (particularly depending on power requirements).

[0102] By extending the pulse durations 20 and 21, the discharge of the output capacitors 9 and 10 (which occurs particularly simultaneously with steps b), c), or y), z), respectively) can be at least partially compensated, fully compensated, or even overcompensated.

[0103] In Figure 5, the second pulse duration 21 is maintained for five second pulses 19, after which (i.e., after step c) or z)) the second PWM signal 6 is changed or shortened (again) by shortening the second pulse duration 21. The second pulse duration 21 is shortened again to the first pulse duration 20.

[0104] The pulse durations 20 and 21 are equal to a constant absolute value of the first pulse duration 20 (in step a) or x), or equal to a constant absolute value of the second pulse duration 21 (in step c) or z), i.e., the pulse durations 20 and 21 alternate between these two different absolute values.

[0105] The second pulse duration 21 may be maintained for a specific duration 23 of the first pulse 12, or for a specific duration 23 of the pause 18 between the two first pulses 12.

[0106] Figure 8 shows the drive assembly 29. The descriptions given for Figures 1 through 7 are referenced.

[0107] The drive assembly 29 comprises an electric motor 30, a converter 31 for converting and transferring energy from a battery 32 to the electric motor 30, and a control device 33, where the control device 33 regulates the current 38 transferred from the converter 31 to the motor 30 via at least one power switch 3. The converter 31 is a DC-DC converter. The converter 31 provides the voltage necessary to operate the motor 30. A so-called, or known, B6 / H bridge 43 (the first electrical component 2) is placed between the motor 30 and the converter 31. The converter 31 is connected to the battery 32 via a filter 44. The bridge 43 is controlled by a first PWM signal 4 of the control unit 33, which generates current signals 38 for different phases of the electric motor 30.

[0108] At least one output capacitor 9 is placed between the converter 31 and the bridge 43. This is used to buffer energy, and as a result, fluctuations in the demand of the motor 30 or the bridge 43 can be balanced through the output capacitor. During the discharge of the output capacitor 9 (due to the current requirements of the bridge 43 or the motor 30), particularly at high currents 38, a voltage drop may occur in the output capacitor 9 (see the first trace 39 in Figure 7). Using this method, the up-and-down nature of the voltage 14 in the output capacitor 9 or the voltage drop can now be at least partially compensated (see the second trace 40 in Figure 7), balanced (see the third trace 41 in Figure 7), or overcompensated (see the fourth trace 42 in Figure 7). The second trace 40 reaches the minimum value of the first nominal voltage 41 again only after a certain time 37. The third trace 41 runs between the minimum and maximum values ​​of the first nominal voltage 14. The fourth trace 42 temporarily exceeds the maximum value of the first nominal voltage 14. For this purpose, the converter 31 (second electrical component 8) is applied with the second frequency 7 of the second PWM signal 6. [Explanation of Symbols]

[0109] 1 (Gate) Driver 2. First component (gate or bridge) 3 Power switch 4. First PWM signal 5. First frequency 6. Second PWM signal 7. Second frequency 8. Second component (circuit or converter) 9 (First) Output Capacitor 10. Second output capacitor 11 Rising edge 12 First pulse 13. First current signal 14. First voltage 15 Falling Edge 16. Second current signal 17. Second voltage 18. Suspended 19. Second pulse 20. Duration of the first pulse 21 Second pulse duration 22 Input Voltage 23. Duration 24 Primary side 25 Secondary side 26 Control Unit 27. The first circuit 28. Second Circuit 29 Drive Assembly 30 motors 31. Converter (second component) 32 batteries 33 Control device 34 Drivetrain 35 Automobiles 36 Drive shaft 37 hours 38 Current 39 First Trace 40 Second Trace 41 The Third Trace 42 The Fourth Trace 43. Bridge (First component) 44 filters

Claims

1. A method for operating a driver (1) for an electrical component (2, 8) assembly, The first electrical component (2) is controlled by a first PWM signal (4) having a first frequency (5), A second PWM signal (6) having a second frequency (7) higher than the first frequency (5) is generated in the driver (1). The second electrical component is controlled using the second PWM signal (6), thereby charging the output capacitor (9). At the rising edge (11) of the first pulse (12) of the first PWM signal (4), a first current signal (13) having a first voltage (14) from the output capacitor (9) is applied to the first component. The aforementioned method, a) A step of generating the second PWM signal (6) using a second pulse (19) having a first pulse duration (20), b) A step of detecting when the rising edge (11) of the first PWM signal (4) begins, c) A step of changing the second PWM signal (6) by extending the first pulse duration (20) to the second pulse duration (21), A method having

2. A method according to claim 1, wherein steps a) to c) are performed when each first pulse (12) occurs.

3. A method according to claim 1 or 2, wherein the second pulse duration (21) is maintained for at least two second pulses (19), and thereafter the second PWM signal (6) is altered by shortening the second pulse duration (21).

4. A method according to claim 3, wherein the second pulse duration (21) is shortened to the first pulse duration (20).

5. A method according to claim 3 or 4, wherein the second pulse duration (21) is maintained for at least 20% of the duration (23) of the first pulse (12).

6. A method according to any one of claims 1 to 5, wherein the voltage (14, 17) is changed by at least 10% of the absolute value of the voltage (14, 17) by extending the pulse duration (20, 21) of the second PWM signal (6).

7. A method according to any one of claims 1 to 6, The aforementioned driver (1) is a gate driver (1), The first component (2) is the gate (2) of the power switch (3), The second component (8) is the circuit (8) of the gate driver (1), The gate (2) of the power switch (3) is controlled via the gate driver (1), The gate (2) is controlled by the first PWM signal (4) having the first frequency (5), The second PWM signal (6) having the second frequency (7) is generated in the gate driver (1), The second PWM signal (6) is applied to the circuit (8) of the gate driver (1) having at least one first output capacitor (9) and a second output capacitor (10) in order to charge the output capacitors (9, 10). At the rising edge (11) of the first pulse (12) of the first PWM signal (4), the first current signal (13) having the first voltage (14) from the first output capacitor (9) is applied to the gate (2), and at the falling edge (15) of the first pulse (12), the second current signal (16) having the second voltage (17) from the second output capacitor (10) is applied to the gate (2). The aforementioned method, Starting from a first state in which a pause (18) occurs between two first pulses (12), the process includes steps a) to c), or Starting from the second state in which the first pulse (12) exists, x) A step of generating the second PWM signal (6) using a second pulse (19) having a first pulse duration (20), y) A step of detecting when the falling edge (15) of the first PWM signal (4) begins, and z) A step of changing the second PWM signal (6) by extending the first pulse duration (20) to the second pulse duration (21). Methods that include...

8. A method according to claim 6, wherein at least steps a) to c) or steps x) to z) are performed when each first pulse (12) occurs.

9. A method according to claim 6 or 7, wherein the second pulse duration (21) is maintained for at least 20% of the duration (23) of the first pulse (12), or for at least 20% of the duration (23) of the pause (18) between two first pulses (12).

10. A method according to any one of claims 6 to 8, wherein the gate driver (1) is operated using at least one of the following parameters: *First frequency (5): at least 1 kHz; 20 kHz or less; * Second frequency (7): at least 10 kHz; 100 MHz or less; * Second frequency (7) > 10 × First frequency (5); *Output capacitors (9, 10): at least 1 μF; 10 mF or less; *First (nominal) voltage (14): at least 10V; 20V or less; * Second (nominal) voltage (17): at least -20V; 0V or less; * Input voltage (22) of the second PWM signal (6): at least 5V; 500V or less; *Pulse duration (20, 21): at least 1%; less than or equal to 100%; where second pulse duration (21) > 1.5 × first pulse duration (20).

11. A driver (1) having a control unit (26) suitable for activating a component of electrical components (2, 8), wherein the driver (1) receives or generates a first PWM signal (4) having a first frequency (5) and generates a second PWM signal (6) having a second frequency (7) higher than the first frequency (5); the control unit (26) is suitable for performing the method according to any one of claims 1 to 10, wherein the second PWM signal (6) can be varied in accordance with the first PWM signal (4).

12. A driver (1) according to claim 11, wherein the control unit (26) is suitable for performing the method according to any one of claims 7 to 10, wherein the driver is a gate driver (1), the first component (2) is the gate (2) of a power switch (3), the second component (8) is the circuit (8) of the gate driver (1), and the control unit (26) is suitable for activating the gate (2) of the power switch (3); the gate driver (1) has a primary side (24) and a secondary side (25) electrically isolated from the primary side (24); the gate driver (1) has the first PWM having a first frequency (5) on the primary side (24) Driver (1) comprising at least one first circuit (27) for receiving a signal (4), and a second circuit (28) for generating the second PWM signal (6) having a second frequency (7) higher than the first frequency (5) on the primary side (24); the second circuit (28) on the secondary side (25) comprises at least one first output capacitor (9) and a second output capacitor (10), the output capacitors (9, 10) being able to be charged via the second PWM signal (6), and the gate (2) located on the secondary side (25) being able to be switched by at least partially discharging the respective output capacitors (9, 10).

13. A drive assembly (29) comprising at least an electric motor (30), a converter (31) for converting and transferring energy from a battery (32) to the electric motor (30), and a control device (33), wherein the control device (33) adjusts the current transferred from the converter (31) to the motor (30), and the drive assembly (29) comprises a driver (1) according to any one of claims 11 and 12, suitable for starting the components of the electrical components (2, 8) of the drive assembly (29).

14. A drive assembly (29) according to claim 13, wherein the current, which is regulated by the control device (33), is transferable between the converter (31) and the motor (30) via at least one power switch (3), and the drive assembly (29) comprises a gate driver (1) according to claim 12, which is suitable for activating the gate (2) of the at least one power switch (3).

15. A drive assembly (29) according to claim 14, wherein the converter (31) is a DC-AC converter.

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